Metal-cutting machine



F. MULLER. METAL CUTTING MACHINE. APmcAnoN FILED MAR- 31, 1919. RENEWEDJULY 19, 1922.

1 ,429, 17, PatentedSept. 19,1922.

9 SHEETSSHEET 1.

INVENTOR m 2 w uuummw AT 0 F. MULLER.

METAL CUTTING MACHINE.

APPLlCATION FILED MAR. 31, 1919. RENEWED JULY 19. 1922.

PatentedSept. 19, 1922.

9 SHEETS-SHEET 2.

F. MULLER.

METAL CUTTING MACHINE- "APPLICATION FILED MAR- IN, 1919- RENEWED JULY 19, 1922- 1 429 1 7 I T PatentedSept. 19, 1922.

S SHEETS-SHEET 3.

F. MULLER.

METAL CUTTING MACHINE.

APPLICATION'HLED MAR. 31, 1919. RENEWED JULY I9, 1922.

Patented Sept. 19, 1922.

Ilw m fiwm M nm un 2 m WW F. MULLER.

METAL'CUTTING MACHINE.

APPLICATION FILED MAR. 3|, 919, RENEWED JULY 19, 1922.

-1,4 29,6 1 7, I PatentedSept. 19, 1922.

9 SHEETS-SHEET 5.

I i l \w F. MULLER.

METAL CUTTING MACHINE.

APPLICATION FILED MAR. 31. 1919. RENEWED JULY 19, 1922.

1,429, 17, PatentedSept. 19, '1922 9 SHEETS-SHEET 6.

INVENTUR F. MULLER.

METAL CUTTING MACHINE.

APPLICATION FILED MAR. 31. 1919. RENEWED JULY 19, 1922.

%1. \m. Wmd/H n w w .0 j tn? Y A w F3 8% d9 [Emm- F. MULLER.

METAL CUTTING MACHINE.

APPL|CATION FILED MAR. 31. 1919. RENEWED JULY 19, 1922.

1,429, 17, PatentedSept. 19,1922.

9 SHEETS-SHEET 8. i -.22

v izvmvmiz 0RNEY F. MULLER.

I METAL CUTTING MACHINE- APPLlCATlON FILED ma. 3!, 19:9. msuzwzo JULY 19. I922.

1 ,429, 6 1 7. I at ted Sept- 19, 1922.

9 SHEETSSHEE1 9.

lfl

m aw,

Patented Sept. 19, 1922.

mama

PATENTgO-FFICEQ nninnnnron mnnnnia, on HARTFORD, coNnnorrrcntaes'sIe-Non"no PRATT a m i nnY-coiaenny, or NEW YORK, n. Y., A oonronarron on NEW JERSEY.

METAL-CUTTING Macrame.

Applieafiun filed March 31, ussel-lain).esase i, aene edzrui ie, 1 922. Serial-No. 576,159.

To all whom it my c era:

a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented-certain 116W' and useful Improvements in h/letal-Qi1t-' ting Machines,o fvvh1ch the following 1s a specification.

The invention relates'to a 'i'naehine' which is similar in some respects to that shown in my co encling application fornietal-cut ting machines, Serial No. 201,338, filed November 10th, 1917.] p v One ofthe objects oi the invention 18 to provide a machine of this general type Which is adapted to pro'perlyi orm oi' re-- lieve a milling cutter Which has l-ielical cutting teeth andwhichis adapted tocut tour differing from a straigh line. A machine embodying the invention is adapted to accurately relieve a cutter blanlr havlng a contour conforming exactly to the contour of a formerivhich is inserted in the machine. 1.1L machine constructed in accordance with this invention, is adapted for carrying out the methods set forth in my patents for methods of making milling cutters, hlo 1,348,301,datedfAngust 3,1920, No, 1,348 302,,da-tedAugust 3, 1920, and No. 1, %;8,302;5, dated August'8, 1920, and appl cation Serial No. 826,875, filed. Septei nber 27, 1919,

the applicationbeing a division oi 'the pre ent application acuaer" such as may be thusmade is set forth and claimed inmy patent" for milling cutters, "No. 1,348,295,

clatedAugust 3, 19%, aniil' application Serial No. 368,928, filed March 26,' 1920.- 1;

' A; further object ofthe nvention is to provide an improved means for changing the relationship between the relieving move ments of the tool and the 'rot'ative movement of the cutter blank to conform tohe lrcal teeth, As concerns thls feature, the invention isnotinecessa'rily limited to the cut ting; oi a blank with a contour differing ii'oin straight lines. In accordance with them-- vention set forth in my aforesaid application,Serial "No. 20l,338,the said relationship is varied by changing the rel eving movements of the tool; In accordance (with i the blank.

a conl "the presentinvention, the relationship is va Be itknoivn that I, F IE RIGHM LLER,

riedby Changing the rotativemovement of A further object of the invention is to provide improvedmechanism for varying the rotative movement of the spindle or blan'ln'this' feature of the invention not necessarily being hmlted to use in conjunction "with the other features hereinbefore specified. I a

further object of the invention is to provide an improved mechanism for interinittently feeding thetool and to'provide an intermittent feed'mechanism in'novel c0- operative relationship with the relieving mechanism, with the mechanism whereby hehcold'al"teeth may be cut, and with the mechanism preferably including i a former and former 3in) Wherebythe bla'nkmay be cut'ivith di erent diameters.

Anotherobject of the invention is to provide mechanism for stopping the spindle rotation preferably at the time 'ot' each feeding movement of the tool, this spindle stopping mechan sm being in novel cooperative relationship with the reheving mechanism, with the mechanism whereby helicoidal teeth may be cut, and with'themechanism whereby the blank may bec'ut-with different diameters.

A still further object of the invention is to provide improved mechanism for Withdrawing the tool from the blank preferably at the time of each feeding movement and at the time of each stopping of the spindle, this Withdrawing mechanisn'i having novel cooperative relationship with the relieving mechanism, with the mechanism whereby helicoidal teeth may be out, and With'the mechanism whereby the blank may be cut with different diameters,

' The mechanisi'ns for interm ttent feeding,

[for stopping the spindle and for Withdrawing the'tool are preferably provided in combi'nationwvith each other so as to operate in timed relationsh1p, but it Wlll be understood that so far as certain'p'hases of'the invention are concerned I do not limit myself to the use of all of these mechanisms combination and that each of them orany tWo of them maybe independently useful.

Still another object of the invention is to provide mechanism independent of or supplemental to the withdrawing mechanism for returning the tool and usually the former pin to operative positions. This mechanism preferably serves to return the tool and pin slowly with a minimum pressure.

A further object of the invention is to provide an improved locking means preferably in. combination with the independent returning mechanism for holding the tool and usually the pin in their operative positions.

Still further objects of the invention will be apparent from the following specification and claims.

In the accompanying drawings 1 have shown the embodiment of the invention which I now prefer together with certain possible variations thereof. it will be under stood, however. that the drawings are to be considered as illustrative only and are not to be construed as defining or limiting the scope of the invention. the accompanying claims being relied upon for that purpose.

Of the drawings:

Fig. 1 is a front view with certain parts broken away and others shown in section.

Fig. 2 is a plan view with certain parts shown in section. In this view the covers for the headstock and other gearing are removed for the sake of clearness.

Fig. 3 is a vertical longitudinal sectional view.

Fig. l is a rear view, partly in section. along the line L4; of Fig. 2.

Fig. 5 is an end view taken from the left.

Fig. 6 is a transverse vertical sectional view taken along the lines 66 of 1, 2, 3 and 4:.

Fig. 7 is a transverse vertical sectional view taken along the lines 7-7 of Figs. 1, 2 and 3.

Fig. 8 is a transverse vertical sectional view taken along the lines S S of Figs. 1, 2 and 3L Fig. 9 is a f agmentary plan view showing certain parts of: the tool-carrying slides.

Fig. 10 is a fragmentar vertical longitudinal sectional view taken along the lines 10--10 of Figs. 2 and 7.

Fig. 11 is a fragmentary vertical transverse sectional view taken along the lines 11-11 of Figs. 1 and 2.

Fig. 12 is a horizontal longitudinal sectional view taken along the lines 1212 of Figs. 1 and 7 Figs. 13 and 14 are detailed views of the mechanism for varying the movement of the blank-carrying spindle. the views being taken from opposite sides.

Fig. 15 is a transverse sectional view taken along the lines 1515 of Figs. 1,3 and 14:.

Fig. 16 is a fragmentary transverse sec tional view taken along the line 1G--16 of Fig. 14.

Figs. 17, 18 and 19 are diagrammatic views illustrating one operation that may be followed in cutting cutters with undercut cutting faces.

Fig. 20 is a fragmentary sectional view similar in part to 7 and showing an alternate construction adapted to be used for cutting cutters with undercut cutting faces.

Fig. 21 is a development view of the cam shown in Fig. 20.

Figs. 22. 23 and 2 2 are diagrammatic views showing the relation between. the tori-11ers and tne blanks for cutters with 1121C ercut cutting faces.

Fig. 25 is a diagrammatic view in. some 'espects similar to 17, illustrating another operation that may be followed if it ting cutters with undercut faces.

Fig. 26 is a fragmentary view on an enlarged scale showing an alternate construction of the former and fern er p'n adapted to be used ror cuttin cutters with undercut 27 and 28 are views similar respec- .o Fin. '7' and 8 but showing an alternate construction adapted for use with formers having reversed shapes.

Fig. 29 adetailed view, similar in part to Figs. 8 and and showing a milling cutter suostituted for the lathe tool shown in the ot .er views.

rring to the drawings, 1 represents the main frame or bed upon which the other parts of the machine are mounted. For carrying the blank for the tool to be formed and relieved. there is provider, a headstock 2 preferably also a tailstock 1%. tool holdi ig-and-operating mechanis n is provided. as shown at 4:. Preferabthe headstock and the tailstock 3 are a -ano'ed to hold the blank against longitudinal movement. the tool mechanism a bei g; moved longitudinally along the blank in the manner to be presently set forth. When "ie machine is so constructed. the h d wok 2 is fixedly secured to the l 2d.

formed in part iiaegrallv therewith. as shown. The tailstoclr 3 is adjustable along the bed to accommodate blanks or blank arbors of different lengths.

The headstock 2 is provided w -i her in the form of a worm wheel 9 meshing with a worm 10 on a transverse rotatable shaft 11.

The tailstock 3 may be of any usual or preferred construction, and it is adjustable along ways 12 and 13. It can be secured in adjusted position by means of a clamp 14 controlled by a lever 15; The tailstock spindle is indicated at 16 and carries a center 17. The spindle can be moved longitudinally by means of a screw 18 under the control of a hand wheel 19. For clamping the sleeve in adjusted position there is provided a handle 20. As shown, the center 17 is adjusted into engagement with the end of the arbor B.

The tool mechanism 4 includesa carriage 21 which is longitudinally movable along ways 22 and 23 on the bed 1. Mounted for transverse movement with respect to the carriage 21 is a slide 24, this slide carrying the cutting tool. In most ofthe figures of the drawings I have shown a non-rotary lathe tool 25, and such a tool is preferable for many classes of work. However, the invention is not limited. to a non-rotary tool and when referred a rotary too] can be used, as wil presently be explained. The tool 25 is preferably very narrow, but if desired a Wider tool can be used when constructed in accordance with the method set forth in my aforesaid Patent No. 1,348,302.

As stated at the outset, a machine embodying the invention is adapted for cutting a blank having a varying diameter. The diameter may vary uniformly from end to end of the blank, thus providing a uniform taper, or it may vary in any desired way sons to provide the blank with any predetermined contour differing from a straight line. The variations in the diam eter of the blank are determined by moving the slide 24 together with the tool transversely, and preferably, for regulating and controlling the transverse movements, I provide a former and. a former pin, one carried. in fixed position on the bed 1, and the other carried by the slide 24. As illustrated, there is provided a former 26 carried by the bed and a former pin 27 carried by the slide 24. The former 26 has eX- actly the same contour with which the blank is to be formed and the former pin 27 has exactly the same shape as the cutting tool 25. The pin is detachably secured to the slide so that it can be removed and another pin be substituted. corresponding to a tool differing in shape from the tool 25 which is shown. For supporting the former 26 there is provided a bracket 28 rigidly secured to the bed 1. In order to permit adjustment, the former 26 issecured to a slide 29 which is longitudinally movable along a suitable guideway 80 on the bracket, a

'gitudinal movement.

screw 31 being provided for efiecting lon- The slide can be locked in adjusted position by means of screws 32, 32 engaging a gib 33. To permit the ready attachment of the former,-the slide '29 is provided with a T- slot 34 adapted to receive T-bolts 35 passing through the former. To further assist in holding the former in place and to pre vent any possible free movement thereof,

there is provided a hooked bolt 36 which, when tightened, serves to draw the former back against a suitable shoulder on the slide. In practice, a former 26 is selected having the contour with which the blank A is to be formed and then by means of the slide 29 the former is adjusted longitudinally until it bears the same relation to the former pin 27 that the blank A bearsto the tool 25. When the former pin and tool are exactly opposite the former is adjusted to aposition exactly opposite the blank. As the carriage is moved longitudinally the slide 24'with the tool 25 is moved transversely so as to keep the former pin 27 in I by the slide 24 is a mechanism for effecting regular reciprocating reheving movements of the slide 37 and the tool in suitable timed relation with the rotative movement of the In order that the tool may be adblank. usted for blanks of dliferent sizes, there is provided a tool-carrying slide 38 trans- 'versely movable on the slide 37. For mov ing the slide 38 there is provided a screw 39 rotatable by means of a hand wheel 40. The slide 38 is provided with a transverse by means of T-bolits 43 entering the slot.

The tool post has a tool-receiving aperture is a slide 37 which is transversely movable along a suitable guideway. Carried in part T-slot 41 and a tool post 42 is held in place provided. with a horizontal top wall exactly at the level of the axis of the blank. The tool 25 is put in place with its top surface engaging thehorizontal wall 44 of the tool post and is held in this position by means of a wedge 45.

It will be observed tion described the tool is maintained in parallelism as it moves longitudinally for feeding or inward and outward to follow the contour.

The relieving mechanism for moving the slide 37' together with the tool25 includes a rotatable relieving cam 46 which is mounted on the slide 24 so as to be bodily movable therewith. As shown, the cam is mounted on a longitudinal rotatable shaft 47 mounted that with the. construcin bearings 48 and t9 on a bracket 50 depending at the front of the slide 24. A lever 51 is pivoted between its ends on the slide 2 1 and at its lower end is provided with a roller engaging the cam 16. The upper end of the lever engages an abutment 52 on the slide 37. A coil spring 53 is interposed between the slide 37 and the slide 2 this spring tending to press the slide 37 forward, thus holding the abutment 52 in firm contact with the upper end of the lever 51. It will be seen that when the cam 16 is rotated the lever 51 will be oscillated, thus giving a reciprocating movement to the slide 37 and to the tool The shape of the cam l6 is such that the slide 37 is in ved forward relatively slowly at a uniform rate so that the tool may effect a relieving out, and is then drawn back relatively rapidly so as to withdraw the tool and position it for another cut.

As before stated, the cam 16 is driven in timed relation with the blank rotation. For rotating the cam, I make use of the aforesaid transverse shaft 11. Positioned immediately below the shaft 11 is a shaft 5a which is mounted partly in the main frame and partly in a bracket 55 secured thereto. For connecting the two shafts 11 and 5st there is provided a gear 56 on the shaft 11, a gear 57 on the shaft 54 and an idler gear 58 meshing with the two gears 56 and 57. The idler gear is mounted on a bearing stud 59 carried by an adjustable slotted arm 60. The arm 60 is carried by a hub 61 which assists in supporting the shaft 11. The speed ratio between the two shafts 11 and 5ican be changed by removing one or both of the gears 56 and 57 and substituting other gears of different diameters, it being clear that the idler gear 58 can be adjusted to mesh with such differently diametered lriounted in the said bracket 55 is a vertical shaft 62 and this shaft is driven from the shaft 54: by means of bevel gearing By means of bevel gearing 64: the shaft 62 serves to drive a longitudinal splined shaft 65. This shaft is supported partly in a bearing (36 secured to the bed and partly in bearings 67 in a depending bracket 5 secured to the carriage 21.

Mounted on the shaft 65 between the bearings 67 and splined to the shaft, is a worm 69. This worm meshes with a worm wheel 70 which is connected with a transverse shaft 71. The worm wheel and the shaft are rotatably mounted in a bearing 7 2 formed in the bracket 68, and in a bearing 73 formed on a supplemental bracket 7% secured to the bracket 68. Slidably mounted on the shaft 71 is a bevel gear 75, and this gear is engaged by a bearing 76 on the aforesaid bracket 50 depending from the front end of the slide 2a. The bevel gear 7 5 meshes with a bevel gear 77 on the shaft 47. The bevel gear and the shaft 71 are splined or otherwise suitably constructed so that the bevel gear is rotated, but is at the same time free to move transversely of the machine when the slide 24: is moved. Inasmuch as the bevel gears 75 and 77 are both supported by the bracket 50, they are at all times held in mesh. It will be seen that with this construction power is transmitted from the shaft 11, hrcugh the several parts that have been described, to the shaft 65, and is transmitted from the shaft 65 to the shaft s7 and the cam 16, the connection between the shaft 65 and the shaft 47 being such that free transverse movement of the cam and associated parts is permitted. The cam s6 is given one complete IiO- tation for each tooth of the blank. The machine can be adjusted for blanks with different numbers of teeth by changing the gears 56 and 57 as already explained.

As has already been stated, the machine is adapted for cutting blanks having helical teeth. In order that blanks with such teeth may be properly relieved, it is necessary to effect the relieving movements of the tool in peculiar relation to the rotative movement of the blank so that the relief may be in conformity with the helical teeth. I have stated that the relieving movements of the tool are effected in timed relation to the ro tative movement of the blank; and, for any given position of the carriage, this timed relation is fixed and definite, but when the carriage is moved to bring the tool into a now cutting position, it is necessary to vary the relation between the relieving movements of the tool and the rotative movement of the blank. For this purpose I make use of a mechanism which is in many respects similar to that set forth in my aforesaid copending application Serial No. 201,838. The present construction differs, however, in that l have so arranged the mechanism that the aforesaid relationship is varied by changing the rotative movement of the blank rather than by changing the relieving movements of the tool. While I prefer to change the blank rotation, it will be understood that my present invention in its broader aspects not limited in this respect.

In the construction illustrated, the driving member or worm wheel 9 is not connected directly with the spindle 5 but is connected indirectly by means of suitable gearing 78 which can be supplementally moved to change the spindle rotation. By preference, this gearing is bodily rotatable and includes a rack and pinion, the rack being longitudinally slidable in accordance with the longitudinal movements of the carriage 21. Coaxially mounted with the spindle 5 is a sleeve 7 9, this being supported in bearings 80 and S1 in the headstock. The inner end of the sleeve preferably extends into and has a bearing in. the outer end of the spindle. Associated'with the spindle is a frame 82 which is recessed to receive the outer end of the spindle and engage the outer surface thereof. The aforesaid worm wheel 9 is rigidly secured to the sleeve 79. Slidably mounted in the sleeve 79 is a shaft 83 having rack teeth formed thereon at 84. The shaft 83 is splined to the sleeve 79 so as tobe rotatable therewith. Rotatably mounted in bearings in the frame 82 is a transverse shaft 85 provided with teeth 86 which meshes,

with the rack teeth 84. Also rotatably mounted in the frame 82 is a transverse shaft 87. The two shafts 85 and 87 are connected by spur gears 88 and 89. Also rotatably mountedin the frame 82 is a third rotatable shaft 90. Secured to this shaft is a worm, 91 which meshes with. worm teeth 92 formed in the periphery of the spindle 5 near the end thereof. At the side of the bracket 82 opposite from the gears 88 and 89 there is provided gearing for connecting the shafts 87 and 90. A gear 93 is mounted on the shaft 87, and a gear 94 is mounted on the shaft 90. An adjustable slotted bracket 95 is mounted on the frame 82 and this carries adjustable bearing studs 96 and 97 on which are mounted respectively idler gears 98 and 99.

Carried by the shaft 83 at the outer end thereof is an annularly grooved collar 100.

Rigidly secured to the main frameadj acent the shaft 83 is a longitudinal guide stud 101. Slidablymounted on the stud 101 is a bracket 102 having a fork 103 entering the groove in the collar 100. The bracket 102 is apertured to receive a longitudinal rod 104. which is connected at its right-hand end with the carriage 21. The bracket 102 can be clamped to the rod 104 in any desired relative position, clamping being effected by means of screws 105, 105 provided with halidles 106. i

It will be seen that when the carriage 21 is moved longitudinally along the bed the rod 104, together with the bracket 102, will be moved at the same time and to the same extent. By reason of the engagement of the fork 103 with the collar100 the shaft 83 is similarly moved, thus moving the rack teeth 84. When the rack slides longitudinally the pinion 86 is turned and this serves, by means of the gearing and the several shafts that have been described, to turn the movement of the spindle is determined by the longitudinal movement of the rack 84, which in turn is determined. by the longitudinal movement of the carriage 21 and of the cutting tool 25 carried thereby. Inasmuch as the relieving cam reciprocates the tool with a frequency which is normally uniform, and inasmuch as the spindle and the blank are given a changed rotation which is other or'both of the gears 93 and 94 and substituting other gears of different diameters.

The idler gears 98 and 99 canbe properly.

adjusted to mesh with such differently diametered gears. It is also possible to cause the relative movements of the spindle to' take place in either direction in conformity with helical teeth inclined. ineither direction. As illustrated, the machine is adjusted for cutting teeth with left-hand helices. For cutting teeth with right-hand helices the idler gear 98 is removed and the gear99 is adjusted to mesh directly with the gears 93 and 94. WVhen it is desired to cut a blank with straight teeth instead of helical teeth,

the gearing is rendered ineffective, as for instance by loosening the clamping screws 105, thus permitting the rod 104 to slide freely through the bracket 102. By loosening the clamping screws 105 it is possible to preliminarily adjust the carriage without affecting the position of the spindle and blank. ,When the cutter and the blank have been properly adjusted relatively, the handles 106 are turned to connect the carriage with the mechanism for controlling the spindle rotation. From the foregoing description it will be observed that in following helical teeth as described, the blank is rotated in each instance through a little more or a little less than one revolution, as required for right-hand or left-hand hellces. It will further be seen that during each rotative movement of the spindle and blank a whole number of relieving movements are effected. p

-The blank A, shown in Figs. 7 and 8, is provided with teeth having their front cutting faces arranged exactly radially. Frequently, however, it is desired to provide a cutter with undercut or hooked teeth; that is, teeth having their front cuttingfaces inclined with respect to radial lines. cutter is set forth in my copending application for milling cutters, Serial No. 323,110, filed Sept. 11th, 1919. For cutting a blank with. undercut faces, it is necessary to Vary Such a. p

blank diameters.

the ordinary relation between the relieving movements of the toolv and the rotative movement of the blank as the cutting tool moves inward or outward to conform to different When such blanks are to be cut, the mechanism heretofore described maybe somewhat modified.

One way of varying the relation will be understood by reference to the diagrammatic Fig. 17. In this view 2% may be considered to be a fragmentary sectional view taken at themaximum radius r of a cutter C having undercut faces. former and the former pin, the cutting tool 25 is at a distance r from the blank axis and is in position to engage the point of the tooth shown and cut the proper relief line 07-61 thereon. The tooth section at a smaller radius r is shown at t. For this radius, without special provision being made, the tool 25 would be in the position indicated by dotted lines at the distance 1" from the blank axis. However, by reason of the inclined cutting face on the blank, the blank tooth would not be in engagement with the tool but would be separated therefrom by the angle on. The tool, however. would immediately start its inward relieving movement notwithstanding the fact that the blank tooth had not yet reached it, and the result would be the cutting of an incorrect relief line (Z(Z. For a still smaller radius 1' of the blank, as shown at t". the result would be similar except that the point of the tooth would be separated from the tool by a greater angle m, with the result that he incorrect relief line (Z"d" would be further from the correct relief line 0ld.

n order to avoid he errors which would occur. as shown in Fig. 17, I vary the relationship between the relievingmovements of the tool and the rotative movement of the blank in such away that the tool, as concerns its relieving movements, is always in the same position when engaged by the front edge of the tooth. This will be clear from an inspection of Figs. 18 and 19. Fig. 18 shows the tool at the same radius r from the blank axis as was shown in Fig. 17, but the relation of the relieving movement has been so changed that the blank is in position to be engaged by the point of the tool when the relieving movement starts. The tooth is therefore cut with the correct relief line (Z-(Z. Similarly, in Fig. 19. the tool is shown at the same distance r from the blank axis as was shown in Fig. 17, but the relation of the relieving movement has been so changed that the blank is in position to be engaged by the point of thetool when the effective relieving movement starts. The tooth is therefore cut with the correct relief line (Z-d. It will be seen that the operation, as illustrated in Figs. 17 to 19, is in no way effected by or dependent on the lon- Under the control of the gitudinal inclination of the cutting faces. In other words, it is immaterial whether the cutting faces be helical or straight.

The required variations in the relationship between the relieving movements of the tool and the rotative movement of the blank can be brought about either by changing (usually advancing) the blank movement or by changing (usually retarding) the tool movements. 1 have found it simpler, to retard the tool movements, and this is particularly desirable when means are provided as herein disclosed for changing the blank movement to conform to helical teeth. In order that the tool movements may be properly retarded, use may be made of an alternate construction such as shown in Figs. 20 and 21.. This is similar to that already described except that a shaft 71 and the bevel gear 75 are substituted for the shaft 71 and the gear 75 before described. The shaft 71, instead of being provided with straight splines is provided with in clined cam grooves 71, and the bevel gear 75 is provided with pins 75 adapted to enter the said grooves. Fig. 21 is a development of the shaft 71 showing the inclined cam grooves. lVith the pins 75 in the full line position shown, which corresponds to the radius r, the cam 46 is in position to imn iediately start the inward relieving movement of the tool; From the description which has been given of the mechanism for driving the relieving cam, it will be re called that for any given longitudinal position of the tool the cam is ordinarily rotated at a speed exactly in proportion to the rotative movement of the spindle and blank. When the tool is moved inward to a position corresponding to the radius r, the normal rotative movement of the cam is retarded by an angular distance 12 which corresponds to the angle m shown in Fig. 17. lVhen the tool moves still further inward to a position corresponding to the radius 1", the cam is still further retarded through an angular distance a corresponding to the angle m shown in Fig. 17. The result of this retarding of the tool is to cause it to be always in the same position as concerns its relieving movements when the front edge of the tooth reaches it. i

The fact that the blank may not have the maximum radius r is immaterial provided that the bevel gear 75 is made to take the proper positions along the cam shaft 71. In order that this may be conveniently brought about, the former is preferably constructed so as to correspond to the radius of the blank to be out. If the cutter C is to have a maximum radius r, the former 26 is made with the point of maximum radius at a distance r from a given reference line. for instance the center line of the bolts 35,

I If a cutter D is to be made having a.

radius r, then the former 26 is made with the point of maximum radius at the distance 1" from the center line of the bolts. If a cutter E is to be made having maximum radius r, then the former 26 is made with its point of maximum radius at the distance r from the center line of the bolts. -The' views being talren at-the radii r, r. and r respectively as in Fig. '17. In lieu of the former 2'6 ordinarily used there is provided a special former Tl of being provided with, a vertical guide surface, is provided with asurface of revolution constructed. about the center S and having the desired contour at any axial plane. Thesur face of revolution is such that the several radii thereof are the same as the corrcsgonding radii of the cutter C to be formed. The

former-26 is provided with an undercut surface 26 which is at the same angle as the undercut tooth faces of the cutter (7. Co-

operating with the former 26 a former pin 2'7 of spec al form. At any horizontal plane the former pin 27 has the same cross sectional shape as the tool 25, but the fo the pin is curved rearward at points 1, center S of the former. g

Under the control of the former 26 and the former pin 27 the cutting .tooli25 is held at a distance r from the center of the cutter G when the vertical. part of the former pin 27* is at a distance a" from the'center S of the former: For a smaller radius such '1", without special provision being made, the tool 25 would be in' a position at the radius r from the blank. The tool: would immediately start its inward relieving movement notwithstanding; the fact that the blank tooth had not yet reached it and the result would be the cutting ofa'nincorrect relief line, as already fully explainedin connection with 17. When using the con struction illustrated in FigsQO and 21, this error is avoided by retarding the relieving movement of the tool. In accordance with the different operation now to be described, the relieving movement of the tool is not changed as to time but is changed as to position; that is, the tool 25, lnstead of being allowed to take a position at the radius 1 from the center, is caused to take aposition at a radius which is greater by the distance the inclination.

iner 26 instead upper part of the former pin 27 s. The distance 5 is such that the inward relieving movement of the tool, which starts immediately, will enable the tool to properly engage the tooth section If and properly cut the desired relief thereon. at the increasedradius 1-+s because of the peculiar curved shape of the former pin 27 at its upper part, The former pin engages the edgeof the former at a point along the inclined surface 26, the point of engagement beingfat a higher elevation because of The curvature is such that the vertical part of the pin is held at a distance 1-|-s from the center S of the former. Similarly, for the radius 1" the tool 25, instead. of being allowed to take a position at the radius r from the center, is caused to take a position at a radius which is of the tool whichstarts immediately, will enable the tool to engagethe tooth section 25 and properly cut the desired relief thereon.-

The increased radius r+s is obtained by reason of the aforesaid curvature of the his curved part of the pin engages the former 26 at another point along the surface 262 this point being nearer the center and therefore at a still higher elevation.

Y A. former such as 26 illustrated diagram inatically in Fig. 25 would not be entirely practical for the reason that the upper part of the former pin would interfere with the former at places above the inclined surface 26 A simpler and more practical former is shown in Fig. 26, this being marked 26 it will be seen that this is the same in principle as the former 26 but that the body of the former is below the surface 26 instead of'above it. This eliminates any interference with the curved part of the former pin 27 The diagrammatic former 26 is shown as having a radius equal to or exceeding the radius of the largest cutter which the machine is capable of cutting. The former 26 as usually constructed, therefore, has a smaller radius such as 1".

It will be seen that the two independent variations are effected in the relation between the relieving movements of the tool and the rotative movement of the blank. One ofthese variations is dependent upon the longitudinal movements of the tool along the blank and the other of the variations is dependent upon the inward or outward movement of the tool whereby, the blank is cut with different diameters. In the preferred embodiment of the invention, as'

mechanism J. was lil the with n tire stone of rel ation to qods oi cutti undercut cutters sented in mothers o" making moving the along the bed tl ere which on res nut 109 depending fro n "t is supported at i ing 110 formed ii the bed. iiou ted in the transverse sh 112- which is co 2 the screw 107 by means of b gearing." 113. At the front end of the shaft 132 a hand wheel 11%: by means of it he screw crew 10'! do l, 1,...! a 111210138 fire screw l H. in worth secured to may be turned manually to o the carriage. in order that the carriage nisty be moved automatically to feed the tool tron;

suf table echani i m is merge inone cutting position to another mechanism is provided. 1 1i preferably adapted to feed t' termittently, but it will be i cod that as concerns certain phases ()1 the invention 1 do not so lin'iit myself inasmuch as the carriae'e may be moved cont' sired lviounted in the bi; is

pin 115 upon which is 1 a sleeve 1113. Loosely mounted on the sleeve near the inner end thereof is a ear 11? which meshes with a 118 on the shaft 112. Connected with this gear 117 is a ratchet wheel 119. Formed on the sleeve 116 near the outer end are gear teeth "ZOwhich mesh with gear 121 cured to the shaft 112. Keyed to the sleeve 116 is a retchet wheel 1532 sir ar the wheel 119. Loosely mounted on the hue oi the ratchet wheel 192 is a swinging arm Pivot-ally connected with this arm near the lower end thereof is a hill: 1% which is adjustably connected at its lei" hand end with an oscillating crank arm 125. The crank arm is secured to a transverse rock shaft 126 which is mounted in bear- 127 and which carries at its rear end a lever 128. Carried by the lever at the upper end thereof is a roller 129 positioned to be engaged by a cam 130 on a longituc "1. lrlounteo on the swing- The shaft 131 rotateo manner to be presently described and it will be seen that at each rotation thcreot the arm 1% end the crank arm 125 are oscillated.

By means o1 the link 124- the 05 non oi the crank arm 125 is transmitted to the plate the CXtGllt of oscillation of the platebcing adjustable by changing;- the conneotion between the link and the crank arm. By means of one or the other of the pawls or 13 1, one of the ratchet Woods 119 or 122 is turned through a small angle, thus turning the shaft 112 and the lead screw 1. and moving the carriage. t the carriage movement r. b when the pawl is in use, relatively small when the awl is in use. By selecting the proper pawl end by ad justing the crank arm connection the desired amount of carriage movemen may be obtaincd.

Preferably the rotation of the spindle at d of the blank is stopped during the feed ing; movement or" the tool. I therefore provide two alternately acting mechanisms, one serving to rotate the spindle and the blank through one revolution, or approximately 1 e revolution, and also serving to effect the lying; movements of the tool and the icr mechanism serving to effect the longir'mdinal feeding of the tool and preferably also serving to effect other movements to be mechanism for rotating the spindle o blank has already been described in part. iis mechanism including the transshatt 11, the worm 10 and the worm wheel 9. The machine is provided with a main power shaft 135. adapted to be driven in any suitable way, as for instance by means of a belt on a pulley 136. Rot-atably mounted on the shaft 135 is a gear 137, this gear being connectible to the shaft by means of a splined clutch element 138. The gear 137 meshes with a gear 139 on a longitudinal shaft 140. Secured to the shaft 140 is a long gear 141, this gear bein surrounded by a sleeve 1-1-2 which is open at the forward upper side. Slidably and rotatably mounted on the sleeve 142 is a bush ing 1 13, this bushing 14:3 being provided with ears between which a gear 14A: is rotatably mounted. This gear meshes with the aforesaid gear 141 on the shaft 1&0. A third longitudinal shaft 1 15 is provided, this shaft carrying a series of different y diametered gears 146. The shaft 1 15 is connected with the aforesaid shaft 11 by means of bevel gearing 1 17. The bushing %8 can be moved angularly and longitudinally on the bushing 142 so as to bring the gear 144 into mesh with anyone ofthe differently .diame'ter'ed gears 146. A springpressed plunger 148 carried by the sleeve 143 is adapted to enter any one of a series of apertures in the sleeve 142 so as to hold the gear 144, inproper position to mesh with y desired one of the gears 146.. it I element which is adapted to be'engagedby the aforesaid splined clutch element 138 onthe shaft 135. When the clutch. element is in its right-hand position as viewed in Fig. 4, it drives the gear 137 and the several parts connected therewith. When the clutch element is in its left-hand position it drives the shaft 149. A transverse shaft 150 is suitably mounted in hearings in the bed and this shaft is connected with the shaft 14-9 by means of bevel gearing 151 The shaft 150 carries a worm 152 which meshes with a worm wheel 153 on the aforesaid longi v opposite fingers 166 and 167 which are adapted to be engaged respectively by latches168 and 169. These latches are held in engagement with the fingersby means of spring" 170; Referring. to Fig. .4, it will tudinal shaft 131. l v

In the operation of the machine, it is, desirable for the sleeve 79 and for the shaft 131 to each make one complete revolution alternately in succession. In order that the desired alternate movements of the sleeve and shaft may take place, I provide'auto matic mechanism for shiftingthel clutch element 138. The mechanism used'is,simi lar in principle. to that shown and described in my Patent No. 1,273,903,101 driving mechanism,dated July 30th, 1918. The clutch element 138 is provided with an vannular groove into which fit rollers or pro jections on y I is transversely pivoted on the frame and is provided witha roller 155'by means of which it may be moved. Mounted {in the frame above the forked lever 154is a trans verse rock shaft 156. Thisrocl: shaft carries at its rear end an arm 157 in which is mounted aspring-pressed plunger 158. As shown in Fig. 4, this plunger isV-shaped at its lower end and is adapted to engage the roller 155., Secured to the rock shaft 156 at the front end thereof is a lever 159 having upper and lowerarms. Theupper arm carries a roller 160 which is adapted to be engaged by a 0511119315156 161secured to a cam drum 162 mounted on the sleeve '79. 'The lower arm of the lever 159 carries a roller 163 which is adapted to be engaged by a cam plate 164 secured to a cam drum 165 mounted on the shaft 131. When the parts are in the positions shown in Figs. 3. '4 and 6 the sleeve 79 is in motion and continues to turn until the cam plate 161 to its right-hand position.

forked lever 154.. Thislever engages the roller 160and turns the lever 159 in the clockwise direction, as viewed in Fig. 3, or in the counter-clockwise direction, as viewed in Fig. 4. This movement forces the spring-pressed plunger 158 over the top of the roller 155 andthustends to swing the lever 154 in the direction to shift the clutchelementinto position to drive the shaft 149. When the shaft 149 is thus driven, the shaft 131 with the cam drum 165- thereon is driven in the direction indi cated by the arrow in Fig.6. This move ment continues until the cam plate 164 enings.

and tends to move the lever 154 in the direction to move the clutch element 138 into position to drive the gear 137.

Preferably, I. do not dependi solely upon the shifting of the lever 159. for the timing of the movements of the clutch element 138. As illustrated, the lever 154 is provided with be seen that the latch168 serves. to prevent the movement of thele ver 154 "toward the left even after the arm'157has been moved Similarly, the latch 169 serves to prevent the movement of the lever 154toward theright even after thearm 157 has-been moved to its left-hand position. --For releasing the latch 168 there is provided I a vertically slidable rod 171 which is normally pressed upward by a spring172. The upper end of therod is engagedby an arm 17 3 on a short transverse rock shaft 174. This rock shaft carries at its front end'alever 175. Mounted on the lever is a roller adapted to be engaged by a cam projection 1'76 secured'to the worm wheel9. The cam projection 176 is so positioned with respect tothecam plate 161 that the plate first-engages the roller 160 and moves the arm 157 intoposition to shift the lever 154. Subsequently, when the spindle 79 has completed the desired revolution the cam projection 17 6 engages the roller onfthe 1 to the position which is shown in the draw- The spring-pressed plunger 158 is again moved over the top of the roller155 a lever 178. At the upper end of the lever 178 is a roller which is positioned to be engaged by a cam projection 179 on the cam drum 165. The cam projection 17 9 is so positioned with respect to the main cam plate 16& that the plate first engages the roller 16S and moves the arm 158 into position to shift the lever 1554. Subsequently, when the shaft 131 has completed the desired revolution, the cam projection 179 engages the roller and the lever 178, thus turning the rock shaft 177 to release the latch 169. The latch having been releasec, the lever turns under the action of the spring-pro.cod plunger 158 and disengages the clutch clement from the shaft 149 and engages it with the gear 137. It will be seen tiat by means of the mechanism described the spindle 79 serves to stop itself after making a complete revolution and to start the shaft 131. Similarly the shaft 131, after making one complete revolution, serves to stop itself and start the spindle '79. Thus these two parts operate alternately in continuous succession.

It is desirable to feed the tool longitudinally while out of engagement with the blank, that is, when the tool is opposite the groove between two teeth of the blank. The blank is therefore preferably mounted in .the spindle so that at the position of stopping the tool will be opposite a groove. The grooves are helical but the spindle and the blank are supplementally turned at each longitudinal movement this supplemental turning exactly compensating for the inclination of the grooves and insuring the stopping of the blank with a groove opposite the tool.

Preferably the tool is withdrawn at the time of each longitudinal movement, the former pin also being withdrawn from on gagement with the former. This withdrawal is effected. by mechanism operated by the shaft 131, the withdrawal being thus properly timed with respect to the feeding movement. Associated with the slide is an abutment 180 which is engaged by the upper end of a lever 181 longitudinally pivoted to the carriage :21. The lower end of the lever is provided with a roller which is adapted to be engaged by a cam plate 1853 on a cam disk 183 secured to the shaft 181. At the beginning of the rotation of the shaft 181 the cam plate 182 engages the roller on the lever 181 and swings it in the counterclockwise direction, thus moving the abutment 180 together with the slide 24 toward the front. In this way the tool 25 is withdrawn from the blank and the former pin 27 is withdrawn from the former 26. its the shaft 131. continues to rotat, thecam 180 operates the feeding mechanism in the way already described. and the carriage is moved longitudinally along the bed. After that the cam plate permits the leverlSl to return tothe position shown, and the slide 1 is permitted to move rearw rd carrying the tool 25 and the former pin 27 to their operative positions. It will be seen that by thus withdrawing the former pin from the former at the time of longitudinal movement, I avoid any diiiiculties incident to forcing the former pin along the former while in contact therewith. if the former pin were maintained in contact with the former at all times difliculty would be experienced in effecting the longitudinal movement, particularly at places where the contour of the former sharply inclined.

Preferably the former pin is restored to engagement with the forn r by a relatively slow movement with a minimum of pressure, so that there will be no tendency to bend or distort the pin or to secure uneven contact between the pin and the former. For this purpose 1 provide a mechanism for returning the carriage which isentirely independent in its operation from the mechanism for withdrawing it. The before mentioned abutment is not connected directly to the slide 2 1 but is connected to a'second slide 18 1 which is transversely movable independen ly of the first slide 2l.- Springs are in erposed between the slide 1841 and the carriage 21 and these springs tend to move the slide 18 1- rearward, thus holding the abutment 180 at all times in engagement with the lever 181. I

The tvr slides 2 1 and 18 1- are ordinarily connected by a lock. is shown most clearly in 7? 23, 8 and 9, the loci; includes a plate IP86 located in a recess in the top of the slide l. The pl ate is provided with a boss which )l'OjGC'tS downward through a slot in the tide, and threaded into this boss is a vertical itu; 'llhis stud extends through and losel iits an aperture in the slide i to the slide 18% aretwo small bellcrsnir levers 188, these levers having hori zontal upper arms nnich engage a collron the stud 187. The lower ends of the levers are adapted to be engai d a irrpered cam bushing 189 vertical movable on the stud. When the bushing lower position, as shown. 5 are forced outward, thus d stud 187 downward and forcing L to into clamping engagement with the s ide i l. in

1 i L ilttvlllg a e to beengaged by cam plates 193 and 194 secured to a cam disk 195 mounted onthe and releasing the lock, Subsequently the ently.

' municates at its ends with cylinders 211.; Also formed in the casting 212 IS a' fluid roller is engaged by the cam plate 194, thus moving the cam bushing 189 downward and re-engaging the lock.

1 have already stated that a supplemental mecha-nisin is'provided for returning the slide after it has been withdrawn in the way before described. Preferably, in order that this supplemental returning mechanism may operate without being affected in any way by the return movement of the slide 184, and in order further that the slide 24 may be returned with a minimum of effort, I provide a supplemental means for supportin the slide 24 after it has been unlocked from the slide 184. As illustrated, the carriage 21 is provided near its front and rear with transverse pivot pins 196 and 197. The carriage is slotted adjacent the pins, and in these slots are positionedar'ms 198 and 199 respectively pivoted on thesaid pins. with rollers 200 and 201 which are adapted to engage the bottom of the slide 24. The

201. upward so as to lift the slide 24 off from the slide 184 and support it independ- The actual raising of the slide may be but a few thousandths of an inch. For re turning the slide 24 rearward as soon as has been released by the lock and elevated by the rollers, there are provided coil springs 205. Preferably these springs are located in long transverse cylindrical apertures 206 in the slide 24. The springs abut at their rear ends against plugs 207 threaded into the apertures, and at their front ends abut against heads 208' on transverse rods 209.

The rods 209 extendthrough central openings in the plugs 207 and are connected at their rear ends with brackets 210 on the carriage 21. Preferably the heads 208' are in theform of pistons and the forward parts of the apertures 206 constitute cylinders 211 in which the pistons 208 fit and move. Se-

cured tothe slide 24 is a casting 212 having a transverse passageway 218 which comreservior 214. Leading from the passageway 213 into the reservoir '214 is a re The arms are respectively provided stricted aperture 215 which is preferably controlled by an adjustable needle valve 216.

Leading from the reservoir 214 back to the passageway 213 is an automatic check valve 217. The cylinders 211 .togetherwith the passageway 213 and a part of the reservior 214 are filled with a suitable fluid, which is preferably a liquid such as oil. It will be seen that as soon as the carriage 21 has been elevated and released from the slide 184, the springs206 tend to move it rearward. This tendency,however, is resisted by theengagement of the pistons 208 with the liquid in the cylinders. This engagement forces the liquid. out of the cylinders into the passage way 212-land thence into the reservoir 214 through the restricted aperture 215. The liquid can pass through this aperture only relatively slowly, and thus the return movement of the slide is made to take place very slowly. When the slide is moved quickly forward at the timeof next'feeding, the check valve 217 opens to permit the liquid to flow from the reservoir 14 back to the passageway 218'and the cylinders 211. The slow return movement causes the former pinto engage the former gently and with a minimum force, so that there is little or no tendency to bend or deflect the parts.

It will be noted that the several cams 130, 182, 193 and 194 are so positioned in relation to each other that the operations which they respectively control take place in the following order. First the two slides 184 and 24 are moved backward in unison, they being stilllocked together. Then the slide 24 is unlocked fromv the slide 184 and is at the "same time elevated on the rollers 200 and 201. Ator about the. same time the carriage is moved longitudinally to feed the tool to a new cutting position. Then the slide 184 is permitted to return to its normal position.

' In. the meantime the slide 24 is bein moved slowly rearward under the control of the springs 205 and the fluid regulating mechanism. After the completion. of the return movement of the slide 24, the rollers 200 and 201 are lowered and the slide is again locked to the slide 184.

In order that the slide 24 may be manually released from the slide 184, I provide a lever 218 which is secured to the rock shaft 191. For moving the lever 218 there is pro- 'vided a wrench 218 as shown in Fig. 9. It will be seen thatthe operator, bymoving the lever 218, can turn the rock shaft, thus raismg the cam sleeve 18.9 and releasing the look. For moving the slide 24 forward manually, there is provided. a segmental gear 219 

